Updated 4th January 2024

Inflammation and your gut: Expert guidance to improve your health

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    Did you know that you can potentially extend your life by 10 years if you eat the right foods — even if you start later in life?

    You may have heard that inflammation is linked to a range of chronic conditions. But did you know that it’s also a good thing that can save your life?

    In today’s episode, Prof. Tim Spector and Dr. Will Bulsiewicz describe how inflammation affects the gut microbiome and how your gut reacts to different foods. They also discuss microbial diversity and its pivotal role in reducing inflammation.

    Dr. Will Bulsiewicz is board-certified in internal medicine and gastroenterology. He’s also a New York Times bestselling author. Dr. B has won multiple awards and distinctions for his work as a clinician.

    Prof. Tim Spector is a professor of genetic epidemiology at King’s College London, director of the Twins UK Study, scientific co-founder at ZOE, and one of the world’s leading researchers. He's also the author of Food for Life, his latest book focusing on nutrition and health.

    If you want to uncover the right foods for your body, head to zoe.com/podcast, and get 10% off your personalized nutrition program.

    Follow ZOE on Instagram

    Download our FREE guide — Top 10 Tips to Live Healthier.

    Is there a nutrition topic you’d like us to explore? Email us at podcast@joinzoe.com, and we’ll do our best to cover it.

    Episode transcripts are available here.

    ZOE Science & Nutrition

    Join us on a journey of scientific discovery.


    [00:00:00] Jonathan Wolf: Welcome to ZOE Science & Nutrition, where world-leading scientists explain how their research can improve your health. 

    I'm your host, Jonathan Wolf, co-founder and CEO of ZOE. Today, we're talking about inflammation, critical for our health, but often misunderstood. What if I told you that your gut could be a source of chronic inflammation, and that this inflammation can cause serious conditions like type 2 diabetes, heart disease, and even cancer? 

    And then, what if I told you that it's possible to reverse this? The good bacteria in your gut could actually reduce your inflammation. Today, we're joined by two giants in the world of health, nutrition, and the microbiome. Prof. Tim Spector and Dr. Will Bulsiewicz. Tim and Will are here to help us learn how to lower inflammation and improve our health.

    Tim is a professor of epidemiology at King's College London, a leading authority on the gut microbiome, and my scientific co founder here at ZOE. Will is a board certified gastroenterologist, New York Times best selling author, gut health expert, and ZOE's U. S. medical director. 

    Tim and Will, thank you for joining me today. So you know the drill. We are, of course, going to start with a quick fire round of questions from our listeners. Uh, and for anyone who's new to the show, that means that you can give a yes or a no, or if you absolutely have to, a one sentence, uh, answer. And I'll start with Tim. 

    Can inflammation cause serious long term diseases? Yes. Well, if I have high levels of inflammation in my body Well, I feel it possibly, Tim, can what I eat lead to inflammation after meals?  

    [00:01:58] Tim Spector: Definitely.  

    [00:02:00] Jonathan Wolf: Well, could improving my gut bacteria reduce inflammation throughout my body? Absolutely. And then for both of you, what's the most surprising thing that you've discovered about inflammation? 

    [00:02:14] Will Bulsiewicz: I would say that inflammation is about more than just the immune system.  

    [00:02:20] Tim Spector: I would say that inflammation is Actually about how our body repairs itself and is, is crucial to Aging, body repair, as well as all our immune functions. So, it's, it's incredibly important we get it right.  

    [00:02:39] Jonathan Wolf: So, I'm really excited by this, this episode and I think those answers sort of, sort of tee up why. 

    Because I think, you know, most of our listeners are going to be like me, which is before I met Tim and Sarah seven years ago, I hadn't paid any, like, attention to this idea of, of inflammation. And actually what I'm struck as I've met more and more scientists over the last seven years with Zoe is how often they focus on inflammation. 

    Now, what I do understand now is that it connects to the health of our gut microbiome, right? The sort of trillions of bacteria in our gut and that it can be seriously harmful to our health. But after that, it all gets very complicated. So, um, I'm really excited to have. Both of you here to be able to explain that in a very simple way, but also then to really take us through lots of actionable advice about what we can do to reduce inflammation and improve our health. 

    And I guess I'd like to just start with the simplest question. What is inflammation?  

    [00:03:38] Will Bulsiewicz: I would define inflammation as activation of the immune system. Um, and that activation is typically in response to what the immune system believes to be a threat. Now whether or not it's actually a threat is a different question, but the immune system essentially has said it's time to go to work. We must, uh, protect and defend the body and therefore the immune system gets activated.  

    [00:04:04] Jonathan Wolf: And Tim, is inflammation good or bad?

    [00:04:08] Tim Spector: Essentially, it's designed by evolution to be good. We'd be dead without it because our body Wouldn't react to anything from, you know, a small cut against a rose bush to stop us bleeding to preventing scarring or fighting off some little microbe that was trying to get into, you know, into our mouth and into our guts. 

    So we all need inflammation. And generally we talk about this as acute inflammation is short term inflammation. And it's when it, this normal response gets continued on. That you get what's called chronic or long term inflammation. And that's when the body is in a permanent state of heightened awareness. 

    So it's like looking for a fight all the time. Uh, but often inappropriately because there is no more infection. There's nothing else. It's, it's, it's being tricked into thinking it's got a, got a fight and that, that's where we have a problem.

    [00:05:13] Jonathan Wolf: And the analogy that I, I think about a bit is, I think as, as, as you both know, I broke my toe, uh, a year ago, I sort of smashed it into pieces. 

    And there was definitely a lot of inflammation in that toe afterwards, like it swelled up to this enormous size. And what I understood, in fact, you, you, you were explaining to me is like, that inflammation is good, it's sort of All of this process that, uh, that the body has been triggered to actually go and heal this wound. 

    And interestingly, it lasted for quite a long time, right? I would say the inflammation, you know, didn't fully recede probably for more than six months in that case, but it has now gone. And so I think you're describing that as an example of inflammation working sort of in the way that it's intended, Tim. 

    [00:05:52] Tim Spector: That's right. It is designed there to, uh, open up the blood vessels. You get extra fluid in there. And that in a way gets rid of the debris and the damage and then also these, it sends signals to white cells to come out of your, your blood, get into that system to start, uh, repairing the damage. And so this, this whole cascade of events, which leads to you getting a swollen and a red, a painful dilated toe. 

    Um, is exactly the defense mechanism that you want. And, you know, you notice it as swelling, but eventually you get inflammation around the, the cut. And so, um, you get new cells being driven to that place and they start repairing and laying down new skin. And eventually the whole process after a few months, uh, you know, pretty much goes back to where it was. 

    Unnormal system. So, generally what we've discovered in, in, in health is it, You know, most pathology is when normal defense systems go a bit wrong, and this tends to increasingly occur with age, and as we get slight little defects in how these things happen, often the body's reacting to something it thinks is a threat, but actually it's its own tissue, and that's, you know, your body would go on and attack. 

    Uh, it's own skin, uh, causing funny rashes or it might attack its own joint thinking actually there's some microbe in there that it's got to get rid of. And that's why people get long term arthritis and skin disease and, and in the gut might also get, um, gut colitis because the body's reacting against itself. 

    [00:07:44] Jonathan Wolf: In the same way the to your injury and so if inflammation is good in these examples, I guess the office question is, why is it bad if it keeps on going? You might, you might think that it's great to have it just always on. So, so help help us understand why it's it's not good if there's too much of it, but there's always consequences. 

    [00:08:01] Will Bulsiewicz: There's always consequences to activation of the immune system. So when it's in an acute setting in response to an infection or whatever. Okay. Uh, to bodily injury, those consequences are worth the price of admission because you're, um, you're defending the body in a way that's necessary. But when we're talking about unnecessary chronic inflammation, which is really the, the root of the issue here, the consequences that we receive are not ones that we want or intend, and they can have effects throughout our entire body. 

    Tim mentioned autoimmune diseases, and we could add allergic diseases. Uh, to the list of sort of classic inflammatory things. But actually there, the list goes far beyond this in terms of conditions that are associated with, with inflammation and in many cases, conditions that people would never even think they actually are inflammatory. 

    And so it's important for people to understand that this goes far beyond just like what we think of as, you know, uh, the immune system and activation of the immune system. This is, um, more nefarious in the long, in the big picture. Uh, in terms  

    [00:09:09] Jonathan Wolf: of our health and well, just to make sure that I've got that, what you're saying is if you have this like long term inflammation for years rather than just days or maybe months, actually that increases your risk of really serious diseases like heart attacks and cancer and things like this. 

    [00:09:27] Will Bulsiewicz: Absolutely. And if, and if we go through the, the list of the most common causes of death that afflict our, our two countries, um, what you'll find is that the, the top causes are all inflammatory diseases. So, you know, coronary artery disease, cardiovascular diseases, stroke, different forms of cancer, the vast majority of forms of cancer are inflammatory. 

    Um, as a result of long term inflammation, diabetes is an inflammatory disease, uh, obesity, Alzheimer's, these are all inflammatory conditions.

    [00:09:56] Jonathan Wolf: So it sounds like you're saying basically inflammation is this sort of hidden cause of sort of almost everything that probably people who are listening to this is, are, are worrying about, or at least is one of the causes. 

    [00:10:08] Will Bulsiewicz: I don't think we want to spend an hour doing this, but I could easily generate a list of over a hundred health conditions that are associated with chronic inflammation. And the thing that's important for our listeners to understand is that you may go to five different doctors for five different health conditions, but the root cause that ties them all together is inflammation. 

    And the frustrating part of that is that if that's what ties it all together, why are we not talking about this more? That's the part that's frustrating.  

    [00:10:37] Jonathan Wolf: Well, I think everyone's probably paying attention at this point. Uh, and I guess the follow on question is, is there more of this longterm inflammation today? 

    than in the past, because I think we are obviously aware that there seems to be this big rise in these sort of, um, serious long term chronic diseases, um, compared to the past.

    [00:10:58] Tim Spector: I think we're seeing a change in that in the past people had chronic infections, so it was very common for people to have tuberculosis, for example, which was the classic example of, uh, an acute inflammation that keeps going because you can't get rid of the Uh, the bug that causes the tuberculosis and so your body continues to react against it and you get a similar effect with things like leprosy. 

    And so, often these chronic inflammatory conditions were related to an original infection and we've moved really into an era where we're not being exposed to as many bugs and infections. But we now have these increased level, these autoimmune diseases and these lifestyle Western Diseases that now have an inflammatory component. 

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    So I think we've changed from modern living, from living surrounded by microbes, having a really strong immune system to suddenly, uh, moving to modern life in its sterile form with poor diets, meaning that we suddenly, uh, are much more prone to things like food allergies and maybe some of these, uh, food allergies triggering longer term autoimmune diseases and chronic gut issues. In a way, we've had the defense system hasn't changed, but the challenges have, and maybe it's not as well primed in childhood as it was in the past. And that's one theory is about why. We're getting more of these problems now on top of, of course, our terrible diet. 

    [00:12:29] Will Bulsiewicz: And there's a question that is a classic science question, which is, is it nature or is it nurture? Is it genetics or is it the environment? And Tim, you've spent your life studying this question and genetics don't shift. In humans that quickly now in microbes, they can shift very quickly, but in humans, we don't have the capacity or ability to do that. 

    Um, what has changed is our environment. And, you know, we spent millions of years living in a pre modern environment, pre agriculture environment, and then we spent 12, 000 years in a slowly adapting, slowly changing, um, agricultural environment. But really, if you think about it. We reached a point where science and technology took off in the last few hundred years. 

    And as science and technology took off, we became, uh, evolutionary pioneers as humans. And in the process of doing that and allowing science and technology to shape our environment. Change our environment radically, even in the last 100 years. Um, what we've lost sight of is that those changes have an effect on our body. 

    Those changes have an effect on the microbes and the microbes are responsible for training our immune system. Our immune system. Yeah.

    [00:13:44] Tim Spector: And that's why food allergy really was unknown to medicine before about 1969. When, you know, man walked on the moon. And now it's one of the commonest things you see in schools. 

    So something quite dramatic has happened in our interaction of our immune system, uh, to train it when we're kids that's, uh, was, was really different before and after that sort of watershed time. And I think that's, that's really fascinating. And that's really just a glimpse of what. It's happening in many other diseases.

    [00:14:18] Jonathan Wolf: I think what you're saying is, levels of sort of long term inflammation are much higher than in, than in the past, and particularly that when you had them in the past, I think you're saying, Tim, that often came from some like active disease that you had, like leprosy. I haven't met a lot of people walking around the streets of, you know, New York or London or LA with leprosy, so I feel that is no longer like the, the core driving issue of inflammation. Is this fair, Tim?

    [00:14:44] Tim Spector: In India and Nepal that I visited, there's still many leprosy hospitals, but TB, its cousin, is very, very common. Got it.  

    [00:14:52] Jonathan Wolf: But in terms of like driving the rates of cancer and diabetes and all the things you're talking about, it's not, it's not leprosy or TB that is causing this anymore, correct? 

    [00:15:04] Tim Spector: That's correct. Yeah, that's right. And that's just the way the immune system's working differently.  

    [00:15:09] Jonathan Wolf: And so what you're saying is there's this really high level of inflammation over years that's been caused by our environment. Hi. Were you surprised to learn how important a role inflammation plays in serious diseases? 

    I know I was. Now it means a lot to me and the whole team that you are listening to this. Each week we put such a lot of hours into this podcast. And we release the show for free without ads to help millions of people improve their health with cutting edge science. In return, all I ask is that you help us on this mission by hitting the subscribe button below. 

    It really helps. Thank you. And on with the show. Most people listening are over the age of five, right? They can't change what happened in those first five years, but clearly they have a lot of, uh, control over the food they're eating and maybe some other aspects of their, their environment. So how does, how does food play into this, this story of raised inflammation? 

    [00:16:04] Tim Spector: Well, until recently, Um, food was sort of vaguely discussed as, uh, in terms of, oh, pro inflammatory diets and these things and, but there wasn't really much science to back it up. It was fascinating when, um, in the Zoe Predict study, uh, Sarah Berry was leading this work and, uh, found that when people had very large, uh, sugar spikes and particularly fat spikes after a meal, remember these vary tenfold between people, that was also associated with big increases in inflammatory markers. 

    These are, um, little tell tale signs in the blood that your immune system is really activated and trying to kill off other things and being very aggressive. And so, most ultra processed food would cause, in some people, these really inflammatory spikes. And if you were having a snack every two or three hours, you'd be triggering This inflammation every few hours for, you know, 14 or 16 hours a day. 

    So your body was in this state of high tension, excitement, you know, the immune system was, come on, waiting for someone to attack and would sometimes mistakenly attack things that it wasn't supposed to and, uh, Really fool the body to think it was in, in, in a war footing. And that's what many people in our populations in the Western world are constantly in, who are eating junk food regularly. 

    Their body thinks it's, uh, in a crisis situation. And so everything is going full alert. It's not trying to repair itself. It doesn't have time to repair itself. It's, uh, really sending out all the wrong signals to the body. And that's why we get these problems in all these other organs in our brain, our heart, et cetera. 

    So, realizing that certain foods in certain people, uh, will cause these inflammatory spikes, uh, is really important. And we also know that our gut microbes can dampen that down as well. So, that, that's also really important that, uh, as well as our, you know, genes which partly control our immune system. 

    We've also got the genes in our microbes that also, uh, can produce anti inflammatory dampening down signals to sort of put out these hot embers. So it's, it's been likened to lighting lots of fires, which normally are fine and they go straight out, but if, if you keep doing it, it's like you've got these hot coals in your body in a permanently heightened state, which means that you can't function normally, you can't do the normal repair processes, you're more likely to. 

    Miss a cancer, more like to badly repair somebody's body so you age faster. This is, I think, the modern equivalent of what, uh, long term inflammation is doing to us all. And basically, our diet and our gut microbes are at the heart of it. 

    [00:19:05] Jonathan Wolf: It's a slightly scary story, isn't it, Tim, that you talk about? You touch a little bit on sort of blood sugar and blood fat. 

    Could you explain a little bit more about what's going on? Somebody's thinking, you know, who maybe is new to this, um, and they're thinking about, you know, they're eating something. How does that link through to the sort of the spikes that you're talking about?  

    [00:19:24] Tim Spector: We see in studies that we did like the ZOE predict study, people are wearing a blood sugar monitor so we know what their blood sugar levels are every few minutes. 

    And when you eat something like a breakfast muffin or a cookie, uh, after around 30 minutes you'll get a peak in your blood sugar and after about 2 to 4 hours you'll get, uh, start to get a peak in your blood fats. And At those peaks, um, that means your body's under stress if it stays there too long. And we think the body is, is seeing that as a, a threat it has to deal with. 

    It's causing some general stress to the, the system, and in response, the body then pumps out these inflammatory chemicals which are arming the immune system to help deal with it. In a way, help deal with getting that fat out of the system. And, uh, trying to initiate some sort of repair. And it's a failed system because it's never really going to work in that way. 

    And that's why we, we think that people who have too much fat in their system, say four to six hours after a meal, these little particles of fat get stuck in the, in the blood vessels and They trigger even more inflammation and, uh, that irritates that whole system and makes it more likely over time to build up plaque and, and heart disease. 

    So, we think there's a real link between not only what you eat, but how you respond to that food, how quickly you get rid of it, and how big that, uh, immune reaction is to it. You put those things together, it's a, it's a nasty cocktail for many people. You  

    [00:21:15] Will Bulsiewicz: know, and Tim, one of the things that filled in some of the puzzle pieces for me when I read that study, the predict study that you and Sarah were a part of, uh, was that the inflammation peaked six or eight hours after the meal. 

    So there was this buildup and lag that took place. And if you think about this, people who are snacking 10 o'clock at night. You're essentially kicking your body into a constant state of inflammation because that's peaking in the middle of the night and then just starting to come down you wake up in the morning and it just fire it back up again. 

    [00:21:46] Tim Spector: And that's why fasting overnight is probably useful because your body. Get dampened down that inflammation and why continued snacking, uh, generally is pretty bad for your metabolism.

    [00:21:58] Jonathan Wolf: I think some people listen to this and say, well, hang on a minute, you're saying I can't eat, but I don't think that's the message, is it? 

    It's not that like all food causes this or even that having a rise in your blood sugar or your blood fat is bad. It's not talking about the way that these are really big spikes and over and over again in a way in which we probably didn't normally experience them before the sort of foods we eat. Today, is that, is that correct? 

    [00:22:23] Tim Spector: Yeah, that, that's absolutely right, Jonathan, you know, until we did these kind of studies in normal people, we didn't know what a normal blood spike of, of sugar or fat was, so we're still finding our way even back then and those, those first studies, but it's clear that many people can metabolize food and get a small spike, saying their fat, they clear it very efficiently, And there's little or no inflammation left over. 

    [00:22:53] Jonathan Wolf: So it's not like all food is bad, um, right? It's something to do with, um, the sort of foods that we're eating today compared to in, in the past? So  

    [00:23:04] Tim Spector: definitely all foods don't cause an inflammatory reaction. And if you have, say, a bowl of mushrooms and lentils, high in fiber, high in, in good fats and protein, You're very unlikely to see any inflammatory reaction. 

    It seems to be, uh, really with fatty foods that we, we get this big reaction and particularly poor quality fats. These, uh, saturated fats that, uh, you're having meals without fiber. that you find in ultra processed foods and, to a lesser extent, sugary, uh, drinks as well. So, it's those ones that cause a really big peak, say six hours, uh, after you've had your meal, you've still got fat in the system, and then after that, uh, you get this inflammatory reaction. 

    So, it's a long time after your meal. And it doesn't happen in everybody. There seems to be a degree of personalization with that as well. So I think it's, again, we're finding out more and more about how we all respond differently to foods, but. For many people, eating bad foods regularly at regular intervals throughout the day keeps them in a high state of inflammation, which is in a high state of body stress.

    [00:24:22] Jonathan Wolf: So you've got this sort of high level of inflammation because you're just eating all of these foods and probably your environment is like switched on too high all the time. How does the. Gut fit into that  

    [00:24:36] Will Bulsiewicz: story? Well, we talk about the gut microbes on this podcast all the time, but there's an a part of our body that I want to introduce that I think is critically important to this conversation that goes along with the gut, the gut microbes, and that's the gut barrier. 

    So throughout our body, throughout our intestines, there is a single layer of cells and that single layer of cells has the responsibility of separating the 38 trillion gut microbes that are on one side inside our intestines from our immune system, 70 to 80 percent of our immune system. It's on the other side. 

    So first of all, people should know that the home of your immune system is in your gut is in your gut. It's born  

    [00:25:22] Jonathan Wolf: in the bone. I would, I would never have guessed that.  

    [00:25:24] Will Bulsiewicz: And it makes a lot of sense because actually this is where, even though it's the deepest part of our body, paradoxically, this is actually the place where we're interacting with the outside world. 

    The most, our skin is a barrier. Our skin locks the outside world, but the guy, this is the place where, you know, in a way our intestines, it's like a, It's like a beautiful river and that river brings clean water and it brings the nutrients that we need that are life giving. But at the same time, that river at times can be perilous. 

    And there can be things in there that we would prefer to not come into contact with.  

    [00:26:00] Jonathan Wolf: I, I, I'm going to try just for a sec, cause I love only a gastroenterologist could say that our intestines were a beautiful river. I was just thinking about my poor little girl who was violently sick last weekend and vomiting everywhere and whatever that was, it was not a beautiful river, Will, but I'll let you keep going with this beautiful river metaphor now. 

    [00:26:21] Will Bulsiewicz: Well, yes, I have an optimistic, beautiful view of the intestines. So, which is quite different from most other people, it's distorted. Um, so none, nonetheless, um, uh, this is the responsibility of this barrier, which is to allow us to recruit into our body, the things that we really want, the things that we need, and yet simultaneously to protect us from. 

    You know, sort of perilous, uh, piranhas or whatever you want to call it, that we want to basically keep outside and leave it inside the intestines and ultimately poop it up. And so now these three parties, the gut microbes, the gut barrier, and our immune system, they're constantly communicating with one another and they're working together. 

    Our gut barrier that has this responsibility of protecting us, it actually Renews itself every three or four days. So we get a brand new gut barrier, by the way, the total surface area of our gut barrier is massive, larger than a soccer field football in the UK. And yet every single, every single blade of grass, there are microbes there that matter every single blade of grass. 

    And so the way that we ultimately set this up, Jonathan, is that we want a healthy gut barrier to protect us. The stewards of that gut barrier are the microbes. They build the barrier, they fortify the barrier, they make sure that it's intact and able to do its job to protect us. When our gut microbes are healthy, they're able to do their job the way that they're supposed to. 

    When our gut microbes have been beaten up and broken down, they're unable to fulfill their job, and part of their job is actually to help us to maintain that gut barrier. And when that happens, we are allowing access into our body, things that aren't supposed to be getting in there. And the classic thing is something called bacterial endotoxin. 

    And this is something that you'll find with E. coli, salmonella, basically the pathologic bacteria that are a normal part of our body, they can actually get across and they inflame our immune system. And this is a large part of where chronic inflammation comes from. So our gut microbes play an essential role in maintaining this barrier to protect us.

    [00:28:42] Tim Spector: And just to add that when we eat healthy food, like fiber, our beneficial microbes will eat on that fiber and produce chemicals that are then really stimulating our immune system to dampen down any inflammation in the rest of the body. So that's why there's this link between eating good foods and making sure that our immune system is working perfectly, not overreacting. 

    And if anything can dampen down any of these fires, it can't do that if it's not getting the right foods for those particular microbes that are very specialized and, uh, need real foods to eat. They can't just, um, exist on burgers, because those, those microbes tend to produce pro inflammatory substances, things that actually kick up the inflammation more. 

    So, That's how our diet starts to play into this delicate balance that Will's talking about.  

    [00:29:40] Jonathan Wolf: Hi, I want to take a quick break here and tell you about something new we've created. A free guide that will kickstart your journey to better gut health. As we're learning from Tim and Will today, and as our members know through using Zoe, we feed our gut microbiome through the variety of foods we eat. 

    And in return, our microbes give us a wealth of health benefits. They're responsible for so much as we've been learning, from digestion to immune support, and even our mental well being. So how can you nurture your gut in the best way? Which food swaps can you try to nourish those good bacteria? What does a high fiber shopping list really look like? 

    Well, stay tuned to hear Tim and Will's top tips. However, if you want even more support, our free gut health guide shares it all. Emails and actionable tips that are designed to put you in control of your gut health. To get yours for free, simply go to zoe. com slash gut guide. Is it always one way? So is it basically you start with, um, whether or not your gut bacteria are good and then it leads to inflammation in the body or is there also something, you know, is there also a chicken and egg where, you know, I've got inflammation elsewhere and that then shapes my gut microbes? How do we know?  

    [00:31:00] Will Bulsiewicz: It absolutely is a two way street. So when you have inflammation, the inflammation does affect your gut microbes. Um, so ultimately, though, the part that we have more command and control over are the choices that we make with diet and lifestyle, those choices ultimately are shaping the environment of the microbes. 

    When you shape the environment of the microbes, then ultimately, um, you are creating a specific microbiome that can create an anti inflammatory.

    [00:31:36] Jonathan Wolf: And we've  talked about microbiome and bacteria, I'm conscious there'll be some people joining us, you know, at the beginning of the year for whom this might be a bit new, could just help to explain a bit like what that, what those two terms mean and how that ties back to this idea, I think of what people are really interested in here, which is, okay, so I want to reduce, I want to have the stuff that's going to be reducing my inflammation. 

    Um, But also how, you know, what's going on with the stuff that's actually increasing my inflammation.  

    [00:32:03] Tim Spector: So what we mean by microbes are microorganisms. So that means bacteria. It also means parasites. It means fungi and little viruses. But we tend to call them all the same sort of community. And that community is called the microbiome. 

    And there's good and bad guys in there. And if you're healthy, you'll have a good balance of good guys and relatively small amounts of bad guys. And essentially they're all like mini pharmacies pumping out generally healthy chemicals. But the bad guys can be sometimes pumping out chemicals that are increasing inflammation, irritating your body. 

    So you want to get that ratio right and That's where lifestyle comes in. And is it  

    [00:32:47] Jonathan Wolf: possible to reduce the inflammation in the gut? So I think you were both describing this pattern where you could have this really inflamed gut and some awful things were happening, well, which were pretty scary sounding.

    [00:33:06] Will Bulsiewicz: So is it possible to reduce the inflammation or is this a sort of like one way street? You can absolutely reduce the inflammation. And, um, you know, the, the exciting and empowering thing about the gut microbiome is that it is constantly evolving and changing. And it is also extremely forgiving. There's a research that was done almost 10 years ago.

    That was one of the first major papers in the microbiome where basically they showed that in less than 24 hours, After changing your diet, you will start to see those effects take shape within your microbiome. Now, this is not to say that 24 hours is all that it takes to overhaul the microbiome, that would not be true. 

    But the choices that you make today will start to manifest by tomorrow in your microbiome, and it will be a snowball effect. That snowball starts very small, but if you come back and you double down and you keep following with consistency these same patterns, you start to build that snowball, you start to build momentum and that momentum can be an anti inflammatory momentum.

    [00:34:05] Jonathan Wolf: And so what happens when the inflammation is reduced? How does that, what happens as a, as a consequence? We've talked a lot about as it going up. There's  

    [00:34:15] Tim Spector: two effects. We want one inside the gut. You'll get a greater number of beneficial microbes rather than pro inflammatory loving microbes. And so, you get a more helpful set of chemicals being produced and your immune system will then get back into its normal regulation. 

    And it'll be able to carry on repairing the body and picking up cancers and dealing with aging and really perfecting metabolism so you're not wasting energy. And you'll Uh, you, you're feeling healthier and your chemicals going to your brain are improving your mood and your energy. So, it's really getting you back into that, uh, that perfect scenario before in a way this, um, false infection hit the body. 

    So, the idea is to use restabilizing things and because your blood is, isn't having that inflammation anymore, that also acts two ways and again helps. The good microbes overcome the bad microbes in your, in your gut. So, again, this two way process, just as well as it happens on the bad way when you get a disease or an infection, the same thing happens when you can improve your diet, then, uh, all the rest of it falls into place. 

    [00:35:33] Jonathan Wolf: So I'd love, I guess, having sort of talked about how serious inflammation is, how deeply interlinked it is with, uh, you know, our gut microbes, these bacteria to start to talk about, okay, what, what's the actionable advice? What can people do? And I think a lot of people listening to this will be saying, okay, that's great. 

    I want to go and make some changes. Tim, maybe you could start by saying, imagine when people are thinking about changing what they want to eat, what would you be?

    [00:36:05] Tim Spector: Telling them to do in order to really make a difference here, eating a greater diversity of plants, uh, having more color on your plate, having more fermented foods are particularly important. 

    And, um, the fermented food is very interesting because. There are now clinical studies showing that people having several portions a day, really big reductions in their inflammatory markers just after a couple of weeks. We don't know the exact mechanisms, but we do know that fermented foods are probiotics, so they're live microbes, and these people, uh, this was a U.S. study where having lots of different types of microbes, so maybe 30 or 40 different species. Every day, they seem to have a beneficial effect on the resident microbes in the gut. And that meant they were pushing out helpful anti inflammatory chemicals and actually drove down and suppressed the immune system that was previously high. 

    And this was a remarkable result because no one expected this to be quite so dramatic. And there was a much bigger effect just by from fermented food rather than just fiber alone. So This is a real sign that, um, although all those dietary changes we're talking about, whether it's the multiple plants, whether it's the polyphenols in the different color, fermented food is probably the one that's most specific to inflammation in the immune system. 

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    And it's something I think we haven't really paid nearly enough attention to in the past. So, little and often, but I think it's not just having one pot of children's yogurt once a week that's going to do it. It's Uh, several portions a day, probably three small portions a day to get these beneficial effects and, um, at the same time, cutting out some of the negative things in your diet, ultra processed foods, things, foods containing, um, bad fats that we've talked about a lot and we know that from our own experiments, people having all these, uh, highly processed saturated fats in ready meals, et cetera, and, uh, junk foods, they're, they cause these, these particular spikes in inflammation, so cutting them out, And then giving your gut a rest, uh, so it can't spike, and so it can repair itself. I think they're the, the key essential elements that, uh, everyone can do if they want to, um, get a, a nice, even, low inflammatory, uh, state in them. And, and people with many chronic diseases, I think, would benefit from this advice, and most of them are not being given it. At the moment.  

    [00:38:45] Will Bulsiewicz: Yeah, it's interesting that, you know, it kind of boils down to two essential principles from a dietary perspective, add more plants and add fermented food. 

    And these are two, two things that we have done throughout human history that we've lost in the last 100 years. And so restoring that in a way would be restoring a more natural environment for these microbes.

    [00:39:06] Jonathan Wolf: And Will, can you, can you help us understand a bit more about how the plant side of this links through ultimately to this reducing inflammation?

    [00:39:16] Will Bulsiewicz: Well, you know, it goes back to, um, a concept that Tim introduced earlier, which is that these, these microbes have the ability to transform our food. If we were sterile, which we are not, there's never been a sterile human. We've always evolved with these microbes. But if we were sterile, fiber would serve the purpose.

    [00:39:37] Jonathan Wolf: Sterile meaning, not that we can't have children, but that there's no, I just want to make sure I understand this. Yeah,  

    [00:39:42] Will Bulsiewicz: sterile in terms of not having a microbiome. If we lacked a microbiome, which is not possible. All humans have ever, have always had a microbiome. Fiber wouldn't serve the purpose that it does. 

    Because fiber exemplifies our relationship with these microbes. It's mutually beneficial. We consume the fiber. The fiber is actually their food. We don't have the enzymes to break down the fiber and release the nutritional quality from it. But the microbes do, they have actually thousands of enzymes, um, that allow them to go to work, typically in teams, uh, unpacking the fiber and releasing what are called short chain fatty acids. 

    And these short chain fatty acids in my more than 20 years of study in medicine, I can say without any question at all, these are the most anti inflammatory compounds that I've ever come across. And they are responsible. This is how the gut microbes restore our gut barrier. This is also how our gut microbes suppress and control and shape the immune system.

    Um, and it's also how they have an anti inflammatory effect throughout our entire body, not just in our gut, but even as far as our brain. Um, so the way in which fiber ultimately manifests is fiber comes into contact with microbes. Those microbes do us a favor releasing these short chain fatty acids. And in the process of doing that, they're having an anti inflammatory effect on our body. 

    [00:41:14] Jonathan Wolf: So they basically create this magic stuff, these short chain fatty acids, which I've heard you guys talk a lot about, I've literally no idea really what that means, but that's good stuff. And basically the point is we can't get it directly just in what we eat.  

    [00:41:29] Tim Spector: That's right. It doesn't, it doesn't seem to work when you give it as a supplement. 

    People have tried giving them supplements in clinical trials. And, uh, it doesn't work by that. And butyrate is, is, is the one that's used most. And it also smells like putrefying fish. So you wouldn't really want to have it as a  

    [00:41:48] Jonathan Wolf: supplement. So that's not just like, it's not a big part of what we just be clear, right? 

    Cause you know, I don't understand this. Most people don't. It's not like there's loads of these short chain fatty acids. When I like, you know, eat a banana, it's something that actually you need these bacteria inside us to. create out of, um, you know, the regular foods that we might eat.  

    [00:42:08] Will Bulsiewicz: So they always, they always are the product of the microbes. 

    Um, but there are foods that do contain short chain fatty acids such as butyrate. So for example, um, there are dairy products that because the cow has microbes that produces these short chain fatty acids, you'll find it in the dairy products. They're in trivial amounts. They're not known to have the same effect on the body. 

    And most likely what's happening is when you drink them, these fats get absorbed almost instantly into your body, um, without actually like getting to where they're supposed to be. This is a very different thing than to consume fiber and have that fiber wiggle its way down through, you know, eight meters of intestines, uh, 25 feet, and arrive, um, into the colon where the, where the microbes are residing and then be released in that specific location. You know, I think it's important to, to bear in mind. It's not just the short chain fatty acids. It's this process of dietary fiber having this effect in the colon.  

    [00:43:10] Jonathan Wolf: So it's sort of like delivering this medicine, like to just the right place, you know, in the right way. 

    And in this case, though, you know, we We feed the bacteria, the sort of the input to that, and then it actually creates this medicine sort of for us, you know, in, in where it's needed, which is, you know, deep in our gut.  

    [00:43:29] Will Bulsiewicz: That's absolutely right. And this is, this is the, this is the most clear example of the millions of years of co evolution that have taken place between humans and microbes. We need them. They need us. And this is how we thrive together.  

    [00:43:45] Tim Spector: Yeah. And that's where the analogy of them being many pharmacies. is, uh, is really helpful to produce these wonderful chemicals, you've got to give them the right supplies. And so that's what our job is, is to make sure they have the right things to make these amazing chemicals for us.

    [00:44:01] Jonathan Wolf: If I was really thinking, I want to reduce this inflammation, so I want to have, be giving the best sort of foods to the bacteria. You talked about fermented foods, but in terms of feeding the bacteria, what are the other sort of key rules that you'd want people to, to hold on to? So  

    [00:44:14] Tim Spector: a diverse range of plants is important. 

    Uh, because that creates a whole range of diverse different microbes and the more diverse your set of microbes are, um, the more different chemicals they can produce together, the less waste there is, and interestingly, there's a new study showing that the more diverse your microbes are, the less nutrients there are left for invaders, so if you've got a salmonella or something, it can't take hold in your gut because, uh, your community of microbes is Absolutely eating all their nutrients so they, they will literally starve, whereas if you haven't got very many because you have a rather limited diet, uh, new invaders like E. 

    coli or Salmonella, uh, will take over. The different colors are there because they've got these polyphenols in them, which are these defense chemicals, which are a general energy for all your microbes. Uh, in order for them to flourish, they use that as an energy source, uh, as well. So we're, regardless of what they're eating, they all like those polyphenols. 

    And then thirdly, you've got the fermented foods, which are these probiotics that have this effect. We still don't exactly understand why they just pass through the gut, stay a few days, and seem to energize your gut microbes to really, um, get our immune system in order, and then pass through, uh, down the toilet. 

    So that's why you need to have them regularly. So they're the three things that essentially need to happen.  

    [00:45:47] Will Bulsiewicz: But you know, one thing, Tim, with the fermented foods, the study that you're referring to, which was out of Stanford, and it involved, uh, Professor Christopher Gardner, who's on the Scientific Advisory Board of ZOE, um, one of the major findings, in addition to fermented foods reducing inflammation, Is that the addition of fermented foods in a period of just eight weeks, which is exciting and fascinating, we're able to actually increase the diversity of the microbiome. 

    And this is a pattern that we see time and again, because when you look at people who have these inflammatory conditions, specifically the autoimmune diseases. If you look under the hood, their microbiome typically has less gut diversity. So it's quite fascinating that when you move the gut from less diversity to more diversity, you also reduce the, um, the inflammation. 

    It's a pattern that we see time, time and again.  

    [00:46:38] Tim Spector: Yeah. And just, I mean, I I'm constantly told by patients that their doctor has said your immune system isn't very good. So don't eat. Um, fermented foods, and I think, uh, we need to be moving away from this rather primitive advice apart from the very rare individuals who might be having cancer therapy with, you know, literally no bone marrow or no white cells. 

    But I think you'd agree, Will, that the vast majority of people would benefit from having more fermented foods in their diet.  

    [00:47:09] Will Bulsiewicz: I think that that's a myth that really exemplifies how misunderstood fermented foods are and how far we've drifted away from what was a traditional diet.  

    [00:47:17] Jonathan Wolf: Well, I think that's really interesting. 

    Now, for people listening, at this point, it feels like only food can reduce inflammation. But, Will, I think there's a bunch of other things that you talk about, uh, that you can do in addition.  

    [00:47:30] Will Bulsiewicz: I think that there's so much that you can do, uh, But frankly, without even lifting a fork, and that to me is quite empowering because for example, if you're a person, you know, I've seen, I've had, I've taken care of many people with Crohn's disease or ulcerative colitis, and these people have the worst food intolerances. 

    It's very hard for them to do some of the things that we're describing here, you know, to say, eat more fiber, like I fully acknowledge that as much as I want them to do that, that's not easy for them. So perhaps for them, a place to start is to do these other things. And it includes sort of the classics that we always think of. 

    So, for example, sleep. Sleep is, uh, incredibly restorative. And people who, um, get a better night's sleep have a healthier gut microbiome. And when you, in studies where they take people into a sleep lab and deprive them of sleep, it doesn't take long for you to start to see the effects of deprived sleep on the gut microbiome. 

    It happens very quickly. So, sleep. And exercise, by the way, many different forms of exercise have different effects on the microbiome. So don't just always do the same thing. Switch up your routine. But I would recommend both, um, cardiovascular exercise and also weight bearing or strength training. I think both of those are complementary to one another. 

    And then Tim, uh, alluded a bit to intermittent fasting or time restricted eating. And to me, this is an important concept in terms of, um, reducing inflammation and also supporting the gut microbiome. And if we could just do one thing and that would be to have an early dinner to me early depends on, you know, your own personal lifestyle, but that would be before 7 p. 

    m. And then to say no food, no alcohol after dinner, um, and allow your body a period of time where it's now unwinding. And then you go to bed and you have a truly restorative period of time that's low in inflammation. Um, that actually is fantastic for the microbiome and it doesn't take much. You know, we did a study in that study, the big F study, we had people doing 14 hours of fasting, which means that they had a 10 hour eating window during the day. 

    And by doing this, we found a number of different benefits, including energy levels increased, better mood, reduced hunger, and I'm personally excited about this one, less bloating. So, and that's quite simply by making those choices. So once again, there are many different things that we can do that aren't necessarily food that can make us feel better and empower ourselves. 

    [00:50:07] Jonathan Wolf: Amazing. No, I don't think I'm going to be signing up for that. I have to finish all my dinner by 7pm every night, uh, plan anytime soon. Well, but I, I like your sort of like perfect living.  

    [00:50:18] Will Bulsiewicz: Well, I think it's more just, um, I want to get people away from the idea of a midnight snack. Or a nightcap, alcoholic drink. 

    That's what I want to get people away from. Amazing.  

    [00:50:29] Jonathan Wolf: Well, I have to say every night as I'm, um, finally crashing out after finishing the email and eating dark chocolate while watching TV at about 10 PM. I think of the pair of you, uh, you know, sort of frowning on my shoulder at my terrible least short period of not eating, but there's always something it's good. 

    It's good to have something to aspire to. Are there any final thoughts on this for somebody who's like come through this story and is saying, um, okay, so I'm really convinced I want to reduce this inflammation. I'm, you know, I'm worried in fact about how maybe I am on the path towards some sort of long term, you know, serious disease, whether it's heart disease or, um, or diabetes or, or whatever, anything else that you'd want to make sure that they were, we're thinking of as, um, as we come to the end here. 

    [00:51:18] Tim Spector: I would just add that, uh, many people are confused. If they went to the internet and said, I've got inflammation, my doctor said, I've got this new disease and it might go on social media, whether it's TikTok or Instagram, they'd be, uh, confronted with this huge array of weird diets and exclusions, things like alkaline water or potato juice or chlorophyll tablets. 

    Or, um, when I was doing rheumatology, I had patients who were told they could never have anything with tomatoes or aubergines in them ever again. The point is you should be adding things to your diet, not excluding them, unless it's ultra processed. So I think that's the main message I would have for people is, you know, if you understand the key role your microbes are playing, and you're looking to feed more and more of those guys, don't go down the route of Uh, these wacky exclusion diets that have no scientific basis on them and are calling themselves anti inflammatory diets. 

    An anti inflammatory diet is one that is generally good for your gut microbes. I think that's the message I would  

    [00:52:26] Will Bulsiewicz: leave with. It's a diet of abundance that ultimately we need in order to be successful, not restriction. So, and, um, and I think just to get back to these, uh, essential concepts of fiber and fermented foods, and if we could quite simply add these, because the reality is that the opportunities that will have the Biggest impact are the ones that we're not doing. 

    So doing more of what we're currently doing is not going to really make a huge difference. What, what helps is when we take something that we just aren't doing and we know that 95 percent of Americans and 90 percent of British people are inadequate in their fiber consumption. And the average amount of fermented food intake in the United States is zero on a daily basis. 

    So, and if we could just increase that a little bit, we would make a huge difference. And that's, that's where I, I would, um, uh, Encourage people to, to start this year. And also last thing, consistency is extremely important. The choice that you make that you can do on a daily basis. It goes, it gets back to the snowball idea. 

    If you can do it and you can come back and do it again tomorrow, it's going to make a much bigger difference than that one thing that you did that one time. Brilliant.  

    [00:53:36] Jonathan Wolf: Thank you both. I'm going to try and do a quick summary on quite a complex topic, I thought, um, this week. And please, both of you, um, keep me honest. 

    So we started off basically explaining what inflammation is, and you both explained that basically if you didn't have the ability to have inflammation, you'd die really fast of like an infection or like, you know, not being able to cure, you know, my broken toe. So like short term acute inflammation is a good thing. 

    We're built to have that. The problem is that today, many of us get us in a situation where sort of the inflammatory response has been switched on. And it's never switching off. And for people who are therefore in that inflammatory state for year after year, will have this terrifying list of basically every disease that anyone could possibly be worrying about, you're more likely to get it, including I think things like cancer that I think, um, you know, I was really shocked to hear, but also, you know, heart disease, things that you don't really think of as being linked to, uh, to inflammation at all. 

    That there's a lot of reasons for why that inflammation, um, might Be increased, including like our environment and what's happening to us as uh, children. Um, but we talked a lot about how, you know, for those of us who are, you know, adults listening to this is very much shaped by. What's going on in terms of what we're eating? 

    Um, and by the way that that's affecting our gut microbiome, you talked about this incredibly thin layer, I think, Will, between like our body and our microbes and the almost all of our immune system is actually sort of in our gut managing this thing with our bacteria. And that basically the sort of food we eat shapes the bacteria that we have inside our gut, shapes what sort of microbiome we have. 

    And that sadly today. You know, the diet that we eat is a diet which is mainly the diet that the bad bacteria wants to eat and not the diet that the good bacteria wants to eat. So we're ending up with like the wrong sort of bugs which are actually making our inflammation higher. So that's all very depressing. 

    But the good news, I think, is you're saying, you know, if you change your diet, you can change, you know, the, you can increase the number of good bacteria in your gut. And actually, that will dampen down the inflammation. And I, and I think, Tim, you're saying you could positively reduce, therefore, your risks of diseases and your potentially symptoms from some disease. Is that, is that correct?   

    [00:55:58] Tim Spector: Absolutely, yes.  

    [00:56:02] Jonathan Wolf: So that's really exciting. And then you said like there's some really simple practical rules. So firstly, what you eat is really central. Um, eat more plants because plants have the fiber inside them that feed the microbes. And they create then this magic thing called short chain fatty acids, which I think only Will and Tim understand what they are. 

    But for the rest of us, like that's the good stuff that the bacteria make. And so you need to give them the fiber. In order to make the, the, the good stuff. Um, and there isn't a shortcut. You can't just eat like a short-chain fatty acid supplement. It doesn't work. You gotta get this fiber to make all of these different bacteria make it think about lots of different colors because that's, you know, this other sort of concept. 

    Polyphenols, which it means, uh, again, basically lots of foods with these different colors is how I understand it, which again, is feeding the microbes that are, are giving this anti-inflammatory. properties. Um, and then separately, I think both Tim and Will, you've got like more excited about fermented food over the last few years with this new research and that actually just eating quite a lot of fermented foods, right? 

    Not one, you said Tim, once a week doesn't get you there. You're actually got to eat several portions of these. It's quite a high bar, which I have to admit, I often don't hit that could make a difference. And then if people are listening to this, it's not only food that you can do interestingly, like sleep and exercise could both also reduce your inflammation. 

    And I think we wrapped up with this idea of time restricted eating. So having sort of long periods of the day when you. Don't eat so not midnight snacking and then having something at seven in the air in the morning But having maybe 12 whole hours without Eating or in fact if you could get it up to 14 hours Which I never can then you know that might be even even better and finally whatever you do Do not follow any diet that comes about after you click on the words anti inflammatory diet on the internet. 

    Uh, is my takeaway, Tim, because basically you're going to get some totally weird diet where you should exclude things. And I think what I heard was, you know, every good diet is like, it's good for your gut, it's about adding more things in. And finally, it's about consistency because the only thing that's relevant here is something you can stick with, you know, for years. 

    So, crazy diets. you know, aren't going to get you there, something that long term supports you.  

    [00:58:20] Tim Spector: You got it. Brilliant.  

    [00:58:22] Jonathan Wolf: Well, I think everybody has their marching orders and I think there's something incredibly exciting about this idea that there's things that you can do right now that really can reduce your inflammation and can really improve your health for the long term, uh, by basically bringing on all of these microbes to fight in your corner. 

    Wonderful. Thank you very much. Bye bye. Thanks everyone. Bye. I hope this episode has opened your eyes to how important your gut microbiome is in keeping inflammation in check and that you've learned something new from Tim and Will. Are you interested in finding out more about your gut microbiome as I have done? 

    With a ZOE membership, you can understand what's going on in your gut microbiome with the most advanced tests available ,and then receive personalized advice and support on how to eat the best foods to support a healthy gut. So, we can help you feel better now and live healthier in the years to come, backed by real clinical studies. 

    Simply go to zoe.com/podcast to learn more and get 10% off your membership. Join us next week when I'll be talking to Dr. Andy Galpin about how you can improve your fitness to live a long and healthy life. I'm your host, Jonathan Wolf. ZOE Science & Nutrition is produced by Yella Hewings-Martin, Richard Willan, and Tilly Fulford. 

    As always, the ZOE Science & Nutrition podcast is not medical advice. It's for general informational purposes only. If you have any medical concerns, please consult your doctor. See you next time.

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